To find the maximum number of snacks \( s \) that Emma can buy, we can start with the information that each snack costs $3 and she has no more than $18 to spend.
The total cost of snacks can be expressed as \( 3s \), where \( s \) is the number of snacks. Since she cannot spend more than $18, we can set up the inequality:
\[ 3s \leq 18 \]
Thus, the correct response is:
3s ≤ 18